#include "main.h"

/* Adjust these values based on your timer clock and desired WS2812 timings.
   With a timer period of 100 counts, a “0” is defined as a pulse width of 30,
   and a “1” as 70. These numbers may need tuning for your board. */
#define TIMER_PERIOD    100
#define WS2812_0        30
#define WS2812_1        70

#define LED_COUNT       8
/* 24 bits (GRB) per LED plus extra end-frame zeros (50 counts gives >50µs low) */
#define LED_DATA_LENGTH ((LED_COUNT * 24) + 50)

uint16_t ledBuffer[LED_DATA_LENGTH] = {0};

/* Simple structure to hold color values in GRB order */
typedef struct {
  uint8_t green;
  uint8_t red;
  uint8_t blue;
} LED_Color;

LED_Color led_colors[LED_COUNT];

/* 
 * Set a given LED color.
 */
void ws2812_setLED(uint16_t led_index, uint8_t red, uint8_t green, uint8_t blue) {
  if (led_index < LED_COUNT) {
    led_colors[led_index].red = red;
    led_colors[led_index].green = green;
    led_colors[led_index].blue = blue;
  }
}

/*
 * Encode LED color data into a PWM buffer. Each bit of color data is converted
 * into a PWM pulse width:
 *   - WS2812_1 for bit '1'
 *   - WS2812_0 for bit '0'
 * Data is sent in GRB order.
 */
void ws2812_prepareData(void) {
  uint32_t indx = 0;
  for (int i = 0; i < LED_COUNT; i++) {
    uint8_t colors[3] = { led_colors[i].green, led_colors[i].red, led_colors[i].blue };
    for (int j = 0; j < 3; j++) {
      for (int bit = 7; bit >= 0; bit--) {
        if (colors[j] & (1 << bit))
          ledBuffer[indx++] = WS2812_1;
        else
          ledBuffer[indx++] = WS2812_0;
      }
    }
  }
  /* Fill rest of buffer with 0s to generate the reset pulse (>50µs low) */
  for (; indx < LED_DATA_LENGTH; indx++) {
    ledBuffer[indx] = 0;
  }
}

/*
 * Start DMA transfer via timer PWM.
 * This function assumes that TIM2 (or your chosen timer) has been configured
 * in PWM mode with a period of TIMER_PERIOD.
 */
void ws2812_show(void) {
  ws2812_prepareData();
  /* Start PWM on TIM2 Channel 1 using DMA. Adjust the timer handle and channel as needed. */
  HAL_TIM_PWM_Start_DMA(&htim2, TIM_CHANNEL_1, (uint32_t*)ledBuffer, LED_DATA_LENGTH);
  
  /* Wait sufficiently long for the DMA transfer to complete.
     A delay of 1ms is usually enough for 8 LEDs. */
  HAL_Delay(1);

  HAL_TIM_PWM_Stop_DMA(&htim2, TIM_CHANNEL_1);
}

/*
 * Main application entry
 */
int main(void) {
  HAL_Init();
  SystemClock_Config();    // Configure system clock (generated via CubeMX)
  MX_GPIO_Init();          // Initialize GPIO (may be generated via CubeMX)
  MX_TIM2_Init();          // Initialize TIM2 for PWM (configure via CubeMX)
  
  /* Main loop: cycle colors on the LED strip */
  while (1) {
    for (int i = 0; i < LED_COUNT; i++) {
      ws2812_setLED(i, 255, 0, 0);  // Red
    }
    ws2812_show();
    HAL_Delay(500);
    
    for (int i = 0; i < LED_COUNT; i++) {
      ws2812_setLED(i, 0, 255, 0);  // Green
    }
    ws2812_show();
    HAL_Delay(500);
    
    for (int i = 0; i < LED_COUNT; i++) {
      ws2812_setLED(i, 0, 0, 255);  // Blue
    }
    ws2812_show();
    HAL_Delay(500);
  }
}